54
THE COUNTY’S NATURAL ENVIRONMENT
PLANNING ISSUE
Though most of the stationary
sources which emit potential
air pollutants are regulated by
state and federal permits and
standards, significant sources
of air emissions are linked to
land use and lifestyle decisions
which can be guided by local
planning efforts.
What’s New
•
Average daily vehicle miles traveled in Montgomery
County dropped from 19,392,400 in 2007 to
18,045,300 in 2010 as a result of high fuel prices and
weak economic conditions.
•
The number of ozone action days in the Philadelphia
region increased from 10 days in 2000 to 18 days in
2012. Much of that increase is attributable to weather
and changing action day criteria.
•
EPA regulations enacted for coal fired power plants
and fine particulates have reduced emissions within
the region since 2000.
•
The number of days that National Ambient Air
Quality Standards for PM2.5 (fine particulates) and
Ozone were exceeded in the region dropped from a
five year average of 52.2 days (2000–2004) to 24.4
days (2008–2012).
Geology
Climate
Hydrology
Floodplains
Air Quality
Steep Slopes
Soils
Wetlands
Woodlands
Wildlife
Natural Areas Inventory
Air Quality
The air breathed by county residents is made up of various
gases that sustain life. It also contains many other
substances, some of which may cause human harm, damage
to the built environment, impacts to ecological systems,
impairment in overall visibility, and water quality
degradation. Air pollution comes from both mobile sources,
such as vehicles, and stationary sources such as power
plants, factories, building heating systems, and
manufacturing processes. Since air currents can carry
pollutants great distances, millions of people can be
impacted by air pollution from a large source.
A significant portion of the air emissions in the region is
tied to vehicle trips. Though individual vehicle emissions
have been reduced through fuel formulations and engine
efficiencies, the fact remains, the more vehicle miles
traveled and fuel consumed, the greater the amount of
mobile source emissions.
The U.S. Environmental Protection Agency (EPA) monitors
and sets national health standards for six common air
pollutants (ozone, particulate matter, carbon monoxide,
nitrogen oxides, sulfur dioxide, and lead). The Delaware
Valley, including Montgomery County, does not meet the
standards for two of these pollutants—ground-level ozone
and fine particulate matter (PM2.5). The EPA has
designated the Greater Philadelphia Region as air quality
"nonattainment areas" for these pollutants.
Ground-Level Ozone
Ozone in the upper atmosphere shields the earth from the
sun’s harmful rays. There, ozone plays an important role
protecting life on earth. At ground level, where people
breathe, ozone can be harmful to lungs and the environment.
In the summer, sunlight and heat can “bake” pollutants to
form ground-level ozone, also known as smog. Because of
air pollution chemistry, high levels of ground-level ozone
commonly occur during the summer months.
Particle Pollution
Particle pollution is the term for tiny drops of liquid or small
bits of dust, metals, or other materials that float in the air.
Some particles, such as soot or smoke, are large enough to
Emissions from automobiles can be a principal source of smog pollution.
